Electrical system for producing musical tones



Feb. 3, 1931. MlLLER 1,791,319

ELECTRICAL SYSTEM FOR PRODUCING MUSICAL TONES Filed Nov. 5. 1928 -1 7 T I I v 4 14:

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ELECTRICAL SYSTEM FOR PRODUCING MUSICAL [TON ES Application filed November 5, 1928. Serial No. 317,219.

My invention relates to an improvement in a system for producing muslcal tones as disclosed in my United States Letters Patent No. 1,376,288 dated the 26th day of April, 5 1921.

Under the disclosure therein contained it is noted that the system produced primary monophonic music or music in'which the fundamentals follow each other in sequence or tone succession. In the practical con struction of musical instruments under such a system it was usually necessary to use a separate loud speaker for each fundamental or harmonic note produced and it is my object herein to disclose a system in which any note or musical notes, both fundamentals and sharps and flats and other harmonics may be produced not only simultaneously but also with the use of only one reproducing or loud speaker unit. It will appear that as a result of my present disclosure I can produce chordal music and produce it with the use of only one reproducing unit or-loud speaker. The advantage of this system is therefore apparent.

A further object of my present invention is to introduce a better system of volume control so that I may control the volume of each particular octave as well as the volume-of the combined octaves. Furthermore it is a further obj ect'of my invention to introduce into the electrical system a plurality of filterswhich correspond to the stops of an organ so'that by the operation of any one or more of these filters in circuit I may change the quality of my tone to simulate the various notes of an organ for example suchas the reeds or the brasses and even the stringed instruments.

My systemwill be more readily understood by reference to the accompanying/drawing in which like letters and like numbers refer to like parts. The drawing shows a diagrammatic wiring diagram of the electrical system which I usefor my mus'cial instrument.

Generically this system is'the. same as that.

disclosed in my previous patent, namely, one in which an oscillating circuit is used to produce a musical note'with the modification,

owever, that my present wiring and connections enable me to play any number of notes simultaneously through the instrumentality of one sound reproducing unit or loud speaker.

Referring to the drawing, Fig. 1 shows a digrammatic key board each key making contact from aconventional plusB source of electrical energy to 2, the key contactors, which are severally connected through the tuned inductance coil 3, having a variable iron wire core for tuning in the plate circuit of the vacuum tube 7, 4 being a balancing condenser or capacity and 5 the primary of a transformer of which 6 is the secondary being a high impedance output coil, the primary 5 being connected as shown in the grid circuit of the tube, the filament being connected to conventional source plus A and minus A, minus B being also conventionally connected as shown. Each of the squares S, S,'etc., represent the tubes and tube connections for each note of a given octave and each is the same except that they have different variations of inductance and capacity for each note to give them their proper values of frequency of oscillation. Each octave is connected to a variable resistance 8 for the purpose of regulating volume. The octaves 9, 9 and 9", etc., are connected as shown and thence through a further variable resistance 10 for the purpose of main volume control, the circuit as shown then passing through the filter units 11, 12 and 13, each designed as' shown with inductances and capacities either in series or parallel or both. These are connected to the amplifier input at 14 as shown and each filtermay be regulated at the will of the operator by proper stops and relays or both and they function to give different instrumental and solo eflects or different qualities of tone. A is a conventional type audio amplifier, preferably impedance coupled, which gives better coeflicients for load mg, quality and frequency. This amplifier is then connected at 15 to any conventional type of reproducing unit or loud speaker.

It must, of course, be understood that additional amplifiers and loud speakersmay also be connected for remote transmission to strategically selected points especially in an auditorium as well as for giving various shading efiects and other effects.

Having thus described my invention, what I claim and desire to secure by United States Letters Patent is 1. An electrical system for producing mu- 'sical tones including a vacuum tube as a gen- 2. An electrical system for producing musical tones including a vacuum tube for each tonal frequency and circuits associated therewith for each tonal frequency all connected to common reproducing units to produce chordal tones and a plurality of electrical filter circuits connected therewith to vary the quality of said tone.

- 3. An electrical system for producing musical tones including a vacuum tube for each tone frequency desired, circuits associated with the cold electrodes of said tube to oscillate; a transformer coupling in the grid circuit of each tube; the secondary of each transformer for each note connected in common through a resistance volume controland through a plurality of filters to a common reproducing unit.

4:. In an electrical music system, a plurality of oscillation generators for independently generating frequencies corresponding to the several notes of the musical scale, and

means for so combining the outputs from the said oscillation geenrators as to produce chordal efiects therefrom.

5. In an electrical music system, a plurality, of oscillation generators for independently generating electrical frequencies correspondmg tom the several notes of the musical scale, means for so combining the outputs from the said oscillation generators as to produce chordal effects thereof, and a common sound reproducer for all of said generators for audibly reproducing the electrical tones generated i 6. In an electrical music system, apluralthe oscillation generators in such manner as to produce chordal effects therefrom, a lurality of parallellyconnected electric lter circuits connected with the combining means for said generated frequencies, means for connecting said par'allely connected filter circuits With the said combining circuit in such manner as to produce varying quality efl'ects therefrom determinable by the filter circuit connected with the said combining circuit, and a common sound reproducing system for audibly reproducing the electrical frequencies generated.

8. In an electrical music system, a plural? ity of oscillation generators for generating frequencies corresponding to fundamental notes of music, and means for combining said oscillation of fundamental frequencies so as to create as a sound manifestation the efiect of a chordal tone.

In Witness whereof I have hereunto set my hand to these specifications this 31 day of October, 1928. p

FRANK E. MILLER.

ity of oscillation generators forindepend-t ently generating electrical frequencies corresponding to the several notes of the musical scale, means for so combining the several frequencies generated by said oscillation generators as to produce chordal effects thereof, and a plurality of electrical filters connected with said combining means for varying the tone quality of the combined fre- L quencies used to produce chordal effects.

7. In an electrical music system, a plurality of oscillation generators for independently generating electrical frequencies corresponding to the several notes of the musical scale, means for combining the output from 

